Condition responsive control



2 Sheets-Sheet 1 n Inventor: George M. Hausler: by

Hrs Attorney March 16, 1943. c. M. HAusLER CONDITION RESPONSIVE CONTROLFiled Nov. 27, 1941 rig. 2.

Mardi 16, 1943- G. M. II-IAUSLER y 2,314,211

CONDITION RESPONSIVE CONT ROL Filed Nov. 2'?. V1941 2 suegra-sheet 2Figi?.

m rv\ al 87 86 `25 50 33 8g w l :i I9

In ventor:

George M. Hauslem.

I' b5 `His ttor-neg Patented Mar. 16, A1943 UNITED sTATEs PATENT oEFiCEto General Electric Company,

New York a corporation of v Application November 27, 1941, Seria! No.420,652

16 Claims. (Cl. 20G-140) The invention relates to condition responsivecontrol, particularly to control devices such as t electric switches orthe like operable with a diiferential in response to variations in apredetermined condition such as pressure, temperature or the like. y

One of the objects is to vprovide an improved multiple lever operatingmechanism capable of more accurately amplifying relatively small butpowerful movements of a condition responsive element to effect operationof a control device.

l Another object is to provide the improved operating mechanism with animproved multi-function compression biasing spring operating connectionbetween the condition responsive operating element and the controldevice so as to bias all the parts of the improved multiple lever systeminto proper operating relation and thereby take up lostmotion'therebetween as well as take care of overtravel in case thecontrol condition should vary outside ythe normal operating range oi'the control device.

A still further object is to provide the improved operating mechanismwith an improved multifulcrum differential lever mechanism wherebydifferent values of the control condition required to operate thecontrol device to each of two control positions may be controlled byindependently ad- .iusting the fulcrums.

A more specific object is to provide an improved condition responsiveoperating mechanism of the above character in which the severaloperating parts are pivotally interconnected in cooperating relation asa unit with the unit pivotally suspended within a channel frame whichalso carries the improved form of condition calibrating scale as well asthe control switch and the condition responsive operating element.

Other objects and advantages of the present invention will becomeevident from the following description of the accompanying drawings inwhich Fig. 1 is a mid-sectional view of a condi-- tion responsivecontrol switch embodying the invention in a preferred form; Fig. 2 is atop view of the control switch shown in Fig. 1 withv the cover removed;Fig. 3 is Van end view of the control switch shown in Fig. 1 showingmore clearly f switch.- Thelcover |2 has an opening I3 at one endforreceiving the upturned plate Il in which suitable knock-out openingsI5 are provided for receiving the wiring connections of the externalcircuit to be controlled by the switch.

In the preferred form shown, the condition responsive element I8 is abellows sealed within the casing I9 to which the bulb 2l is connected bythe tube 2|, all of which are solidly iilled with an expansible liquidso as to produce contraction and expansion of the bellows I3 uponopposite variations of the temperature of the liquid in the bulb 20. Thecasing I9 is suitably secured to the base I3 so that the operating pin22 extends upwardly from the bottom of the bellows I 8 through theopening 23 formed in the base I0 into operating engagement with the mainoperating lever 25. Other suitable forms of condition responsiveelements may be employed for operating lever 25 if desired. Preferably,the upper end of pin 22 is suitably pointed so as to pivotally seatwithin. the depression 26 formed in the main lever arm 25 and therebyprovide an anti-friction pivotal operating bearing therefor. The mainlever arm 25 preferably is of channel shape to insure stiffness and isprovided with a pair of slotted mounting ears 21 extending upwardly inspaced apart alignment from the channel sides adjacent one end thereoffor receiving in the slots 28 thepin 23 which extends between thechannel sides 30 of the auxiliary motion multiplying lever 3|. Theauxiliary motion amplifying lever 3| preferably is formed of resilientmaterial centrally stiil'ened by a channel shape, as shown, so that itmay be pivotally mounted by riveting one end thereofto the downwardlyprojecting mounting finger 32formed at one end of the channel frame 33,within which all of the parts of the operating lever mechanism thedetails o: the calibrating scale mechanism;

A .lng scale; and Fig. 5 is a top view of the calibrat- 55 are enclosed.The pivotal movement of auxiliary lever 3| is limited by the spacedapart limit stops 34 and 35 which, as shown, are punched inwardly fromthe sides of the channel frame 33. If desired, the mounting nger 32 maybe bent so as normally to bias the auxiliary lever 3| into ensagementwith the lower stop 34, but this is not essential.

The channel frame 33 preferably is provided with suitable guide ears 33aat the four corners thereof which seat within suitable slots formed inthe base l so as to properly position the channel frame on the base whenthe holding down screws 38, shown in Fig. 2, are tightened. The channelframe 33 is provided with suitable openings for receiving the anchoringbosses 31 of an enclosed snap action circuit controlling switch unit 38.In the preferred form illustrated, switch unit 38 is of the improvedvariable opposing bias snap action type more fullyv described andbroadly claimed in the copending patent application Serial No. 403,474,flied July 22, 1941, and assigned to the assignee of the presentinvention, although other suitable forms of variable bias snap actionswitch units may be employed if desired.

Briefly, the improved form of switch unit 38 illustrated has a centrallypivoted contact operating lever 39 formed of magnetic material andvariably biased into the position in which it is shown in engagementwith the stop 40 by the permanent magnet 4| so as to carry theresiliently mounted movable switch contact 42 into engagement with thestationary switch contact 43. Operation of the movable switch contact 42to the circuit opening position is effected through the agency of theopposing variable biasing spring strip 44, one end of which is flxedlymounted on the centrally pivoted lever 39 and the other end of which isengaged by the switch operating pin 45 that slides through a suitableguide opening formed in the mounting boss 31. The permanent magnet 4|serves to bias the movable switch contact 42 to the circuit closingposition until the magnetic biasing force is overcome by the opposingspring biasing force set up in the spring 44 when the operating pin 45The movable pointer 45 extends through slot 33a formed in the scale 33and is flxedly secured to the large adjustment cam 53 which is rotatablymounted upon the rivet 31 extending from the bracket 52 and carrying theresilient washer 33 for holding the cam 63 and pointer 35 in theposition to which they may be adjusted.

As shown more clearly in'Fig. 3, the adjustment cam 65 has its peripheryin sliding seated engagement with the pin 1|) which is flxedly securedto and extends from the main operating lever 25 through the guide slot1| formed in the bent over end 12 of the channel frame 33. Thus theadjustment cam 68 constitutes an adjustable fulcrum having slidingengagement with the pin 13 at the right-hand end of the main operatinglever 25.

An improved multi-function biasing means, preferably in the form of apair of compression springs 15, is interposed between the left-hand endof the main operating lever 25 and the auxiliary motion multiplyinglever 3| so as to normally exert a force therebetween to bias the pin 28into engagement with the upper end of the slots 29. These springs alsobias arm 3| into engagement with stop 34, pin 10 into engagement withcam 86, and in addition provide an overtravel yielding connectionbetween the levers 25 and 3| while transmitting the normal operatingforce and effectively preventing lost motion in the entire motionamplifying lever system.

. As a result, the improved form of motion multiis raised to effectoperation of the centrally pivoted switch operating lever 39 out ofengagement with the stop 40 and into engagement with the stop 48,thereby moving contact 42 to the circuit opening position. Due to thedecrease in the magnetic biasing force occurring when the lever 39 movesaway from the magnet 4|, the switch cannot be reclosed until theopposing biasing force of spring 44 is reduced b elow the decreasedbiasing force of magnet 4|.

In the improved differential operating mechanism of the presentinvention, the sliding movement of the switch operating pin 45 iscontrolled by the auxiliary differential regulating lever 50, whichpreferably is formed of resilient material so as to be pivotally mountedor hinged by securing one end thereof to the auxiliary motionmultiplying lever 3| by the rivet 5|. The other end of lever engageswith the adjustable stop 52 that is provided to vary the operatingdifierential in the manner described hereinafter. The adjustable stop 52is carriedin the path of lever 50 at the end of the' spring strip 53which is suitably secured to the channel frame 33 as by the rivets 54.The position of stop 52 in the path of lever 50 is adjusted by turningthe screw 56 which is rotatably mounted in the top of the channel 33 andis in threaded engagement with the spring strip 53. 'I'he screw 5S isprovided with a pointer 51 for operation over the differentialcalibration scale markings 58 provided on the top of the channel frame33 between the limit stops 59, as shown in Fig. 2.

The main temperature Calibrating scale 89 is curved so as to be carriedupon the bent over fingers 6| of the supporting bracket B2 which issecured to the channel frame 33 by the rivet 63.

plying lever mechanism of the present invention more accuratelytransmits small motions of the condition responsive element, andrequires only one fixed pivotal connection to the channel frame 33;namely, the yielding hinge connection o; the auxiliary lever 3| to thebent over fingers 3 Operation Assuming the main calibration pointer 55set at the particular temperature value of bulb 20 at which it isdesired to open the control switch 38 and also the differentialCalibrating screw set at the particular diiferential temperature valueat which it is desired that the switch 38 be reclosed, the operation isas follows:

As the temperature to which the bulb 20 is subjected increases,expansion of the liquid enclosed within the sealed system causes thebellows I8 to contract and raise the pin 22 thereby rotating the mainoperating lever 25 about its sliding pivotal bearing with the adjustmentcam 66. The amplified rotary movement of the left-hand end of lever 25is transmitted through the compressed springs 15 to rotate the auxiliarymotion multiplying lever 3| about its pivotal mounting on arm 32 whileat the same time maintaining pin 29 in firm engagement with the upperend of. the slots 28, and pin 1U in firm engagement with cam 65. Thisfurther compresses springs 15 to some extent. As a result, any veryslight but powerful movement of the bellows I8 is accurately amplifiedin the rotary movement of the right-hand end of auxiliary lever 3| withpractically no. lost motion.

As the right-hand end of the auxiliary lever 3| is moved upwardly, theauxiliary differential control lever 50 remains in contact with thedifferential adjustment stop 52 until the projecting finger 3|a at theend of the lever 3| engages with lever 50. Thereafter, the auxiliarylevers 3| and 50 both move as a unit to actuatethe operating pin 45 ofthe switch unit. When the switch operating pin 45 has been raisedsumcientlyto build up suificient force in the variable biasing spring 44to predominate over the magnetic force of magnet 4I on the switchoperating lever 30, then the switch contact 42 will be operated with asnap action to the circuit opening position. 'nils willoccur with thebulb 2l at substantially the temperature value to which the adjustablecalibrating pointer l5 is set when the operating mechanism is onceproperly calibrated.

In case the temperature to-which the bulb 2l is subjected shouldcontinue to increase after the opening of the switch, the bellows IIwill-continue to contract, thus stili further 'continuing the upwardmovement of 'the pin 22 and the rotation of the main operating lever 25.When auxiliary lever 3| engages with its upper limit stop 35, furtherupward movement of lever Il and switch operating pin 45 is 4impossible.Then the pair of springs 'I5 will be further compressed. and the slots28 formed in the ears 2l will permit the continued upward movement ofthe lefthand end of the main lever 25 without introducing any abnormalstrains in the lever system. Suitable openings Il are provided in theauxiliary lever Il for permitting the upturned ears 21 to passtherethrough in case of excessive overtravel.

When the temperature to which the bulb 2l is subjected decreases afterthe switch 3l has been opened in the manner described above, the bellowsIl will be expanded to permit the downward biasing force exerted bysprings on lever 25 to'move the pin 22 downwardly. This in turn willpermit the biasing forces of springs 'l5 and spring 44 to lower theright-hand end of the motion multiplying lever 3l awayv from stop 35.However, the switch contact 42 will remain in the circuit openingposition until the biasing force of the spring 44 has been reduced to avalue below the reduced' magnetic biasing force tending to reclose theswitch contact 42. Consequentover the temperature calibration scale 60so as to vary the pointl of engagement of the cam with the pin 'Illthereby. varying the temperature of the bulb 2l required to eifectoperation of the switch to the circuit'opening position. The relativelysmall but powerful operating force of l the bellows Il is amplied withsubstantially no lost motion to eifect the opening movement of theswitch due -to the improved operating connection provided by the biasingsprings 15. The

sliding pivotal bearing between pin 'lll and the l calibrating cam 5 5permits -any necessary slight endwise movement of the main operatinglever 25 to occur. This is also true-of the pointed pivot pin operatingconnection .between the main operating lever :s and the bellows' pm zz.A11 of vlever 25 on the pointed end of the main adjusting screw 8l whichextends through the channel frame 33 and is in threaded engagement withthe arm 82 bent over from the end ly, the switch operating pin 45 mustbe vlowered of the channel I2. The adjusting screw 83 c'arriesa movabletemperature calibrating scale which, as shown more clearly in Fig` 5,cooperates with the pointer 84 formedin the channel frame Il to indicatethe temperature value at which the switch I5 is operated to the circuitopening position. A specially formed rotatable cam element 85 lrotatesabout the adjusting screw 8l as an axis as the cam 86 is of sufilcientthickness to rotatably engage'only with the ends of the threads formedon the screw Il and thus is not in threaded engagement therewith. Therotatable cam 8B is provided Wlthla spiral cam face 81 forengaging withthe right-hand end 'of the auxiliary differential regulating lever 50 soas to vary the position at which the motion of the right-hand end ofthis lever is arrested in the switch closing operation. The rotatablecam B5 carries a pointer 88 extending upwardly throughthe slot 89 formedtial control stop 52, 'I'hereafter the right-hand l end of thediiferential lever 50 will pivot about stop 52 while the left-hand endof lever 50 continues to be lowered due to the continued loweringmovement of the lever 3 I. y When the bulb 20 reaches the predetermineddifferential temperature value corresponding to the adjustment of thescrew 56, switch operating pin 45 will be lowered sulciently so that thereduced magnetic biasing force of magnet 4l will again predominateoverthe variable spring biasing force of spring, and the switch contact42 will be returned to the circuit closing position with a snap action.'The differential adjustment screw 5i, being normally stationary, maybereadily adjusted at any time Without interfering with the operation ofthe movable parts oi the device.. AIn this respect, the presentinvention provides further improvements upon the improved diiferentialadjustment invention disclosed and claimed in the patent applicationSerial No. 403,474 noted above.

With the improved operating mechanism of the present invention, thepointer 85 may be adjusted in the channel frame 33 into cooperatingrelation with the movable scale l! carried by the adjusting screw 80, asclearly shown in Fig. 5. The spring serves to hold the rotatable cam 56in frictional engagement with the arm 82 in the particular position towhich it may be adjusted.

The operation of the switch 38 by the bellows l. inresponse tovariations inthe temperature With the improved Calibrating mechanismshown in Figs. 4 and'5, both of these temperature values may beindicated. directly upon the moving scale 83. In this respect, mypresent lnvention provides further improvements in the improveddifferential calibrating mechanism described and claimed in my patentapplication Serial No. 412,415, filed Sept. 26, 1941.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is:

l. In combination, a control member movable between two controlpositions, opposing biasing means therefor having a reversiblepredominance, a main operating lever having lost motion pivotalconnecting means adjacent one end thereof, an adjustable fulcrum forengaging the other end of said main lever, condition responsive meanshaving an operating member engaging said main lever between the. endsthereof, an amplifying lever overlapping the said one end of said mainlever and interconnected with said lost motion pivotal connecting means,means for rotatably supporting one end of said amplifying lever, acompression spring interposed between said amplifying lever and the saidone end of said main lever to take up the lost motion in said pivotalconnecting means and bias said levers to rotate in opposite directionsabout said pivotal connecting means and thereby provide both a yieldingand a biasing operating connection therebetween, a differential controllever hinged adjacent the other end of said amplifying lever to be movedas a unit therewith to render one of said biasing means predominant overthe other to bias said control member to move from one of said positionsto the other and to be moved relatively to said amplifying lever torender the other of said biasing means predominant over said one biasingmeans to bias said control member to return from said other position tosaid one position, and an adjustable stop disposed in the path of saiddifferential control lever to regulate the said relative movementthereof. v

2. In combination, a movable control member, a main operating levertherefor provided with a pair of slotted ears in spaced apart lateralalignment adjacent one end thereof, an adjustable fulcrum for engagingthe other end of said main lever, condition responsive means having anoperating member engaging said main lever between the ends thereof, anamplifying lever overlapping the said one end of said main lever andhaving a connecting pin extending through said slotted ears, adifferential control lever hinged adjacent one end of said amplifyinglever to be moved as a unit therewith to move said control member fromone position to another position and-to be moved relatively to saidamplifying lever to move said control member from said other position toYsaid one position. means for rotatably supporting said amplifyinglever, a compression spring interposed between the said one end of saidmain lever and said amplifying lever to provide a yielding operatingconnection therebetween, and an adjustable fulcrum for said differentialcontrol lever to regulate the said relative movement thereof.

3. In combination, a movable control member, opposing biasingmeanstherefor, condition return from said other position to said oneposition,andanadjustablestopdispodinthepath of said differential controlmember to regulate the said relative movement thereof.

4. In combination, a control member movable between two controlpositions, opposing variable biasing means therefor, one variable intopredominance over the other to bias said Y control member to move fromone of said positions to the other and out of predominance over theother to bias said member to return to said one position, and conditionresponsive means having a multiple lever mechanism operatedl thereby forvarying said one biasing means and provided with lone adjustable fulcrumfor controlling the operation thereof to vary said one biasing meansinto predominance over the other and a second adjustable fulcrum forcontrolling operation thereof to vary said one biasing means out ofpredominance over the other.

5. In combination, a lever pivotally supported at one end and having apair of levers pivotally connected thereto, a pair of separatelyadjustable fulcrums, each disposed in the path of a corresponding one ofsaid pair of levers, condition responsive means for moving one of saidpair of levers to effect movements of said first vcondition responsivemeans and provided with an adjustable fulcrum and another leverconnected to be operated by said one lever and provided with aseparately adjustable fulcrum, and control means having a memberoperated by said other lever to one controlling position upon variationof said condition to a value determined by the adjustment of one of saidfulcrums and to another control position upon variation of saidcondition to a value determined by the adjustment of both of saidfulcrums.

7. In combination, a control device. a condition responsive multi-leveroperating mechanism for said device including a lever pivotallysupported at one end and having a second lever hinged adjacent the freeend thereof for movement as a unit therewith for operating said controldevice and l.V third lever provided with a lost motion pivotalconnection intermediate the ends of said first lever. conditionresponsive means for operating said third lever, an adjustable fulcrmnat the other end of said third lever for calibrating said mechanism, andan adjustable fulcrum disposed in the path of said second lever forregulating the operating differential of said mechanism.

control member to move from. one control position to another and to haverelative movement v with respect to said lever to render the other ofsaid biasing means predominant over said one biasing means 'to bias saidcontrol member to 76 8. In combination, a first lever having anoperating member hinged thereto, a control device operated by saidmember. a second lever having a lost motion yielding connection for op-9. In combination, a condition responsive element, a floating leverhaving an operating connection with said element and provided with apair of slotted ears in spaced apart lateral alignment adjacent one endthereof and a longitudinal pin extending from the other end thereof,control means having a movable operating member provided with aconnecting pin extending through said slotted ears, a compression springinterposed between said movable operating member and the'said one end ofsaid lever to provide a one-way biased operating connectiontherebetween, means providing a slotted guide for said longitudinal pin,and an adjustable fulcrum for varying the position of said pin in saidslotted guide for controlling the movement vof said operating member.

10. In combination, a control device having a control member eiiectiveupon movement thereof to each of two control positions and ineffectiveduring movement intermediate said positions, a condition responsivedevice having an operating lmember movable in accordance with variationsin a predetermined condition, means for. oper-' atively vinterconnectingsaid Vmembers including a supporting lever connected to be operated bysaid operating member, a` multi-fulcrum lever having a fulcrum forabutment with one end thereof and a restricted hinge connecting theother end thereof 'with saidA supporting'lever to eiect pivotal movementof said multi-fulcrum lever away from said abutting fulcrum about thefulcrum of said supporting lever to operate said control member betweenan intermediate position and one of said control positions and to effecta pivotal movement of said multi-fulcrum lever about said abuttingfulcrum to operate said vcontrol member between said intermediateposition and the other of said control positions,

to Vary the operating differential of saidcon trol member. 11. Incombination, a control device lhaving a control member eectiv'e uponmovement thereof to each of two control positions and ineffective duringmovement intermediate said positions, a condition responsive devicevhaving an operating member movable in accordancewith variations in apredetermined condition, means for oper-` meansfor adjusting one of saidfulcrums to vary the operating differential of said control member.

12. `In combination, control means, condition responsive means having amulti-fulcrum lever mechanism for operating said control means, and

Ameans for adjusting said mechanism including' an adjusting screw forcontrolling one fulcrum of said mechanism and having a rotatablecalibrating scale element and a separately adjustvmulti-fulcrum levermechanism for reversing the predominance of said biasing means to eifectoperation of said control member between said control positions, andmeans for adjusting said mechanism including a pair of separatelyadjustable members having interdependent calibrating elements and eachcontrolling a fulcrum o' said mechanism.

14. In combination, a control member movable between two controlpositions, condition responsive means having a multi-fulcrum levermechanism for operating said member, and means for adjusting saidmechanism including a pair of separately adjustable rotatable membershaving interdependent Calibrating elements and each controlling a'fulcrum of said mechanism.

15. In combination, control means, condition responsive means having amulti-fulcrum lever mechanism for operating said control means, and'means for adjusting said mechanism including a pair of separatelyadjustable, concentric, rotatl operating element, a floating leverprovided with by said operating member for moving said lever about onefulcrum to effect operation of said control member between anintermediate position and one of said control positions and aboutanother fulcrum to eiIect operation of said control member between saidintermediate position and the other of said control positions, and

a lost motion coupling element at one end thereof anda sliding guideelement at the other end thereof and having an intermediate operatingconnection with said operating element, a control device having va'movable operating member provided with a coupling element and a. biasingelement for cooperating with said lost motion vcoupling element toprovide a. one-way `:yielding overtravel operating connectionl betweensaid oating lever and said operating member. and an adjustable stop insliding engagement with said sliding guide element for providing 'afulcrum for said'lever. I

anonce u. Estrema.

